Engine governor



Feb. 28, 1956 2,736,304

R. H. THORNER ENGINE GOVERNOR Filed Nov. 9, 1948 o INC-HES OF &

o MANIFOLD VACUU 500 I000 I500 2000 2500 3000 3500 f ENGINERB M.

FIGJ

W L 84 PIC-3.5

6, INVENTOR a W H 7W I BY l O zficslm: RR M. M ATTORNEY United States The present invention relates to governors for internal combustionengines, and more particularly to engine controlling governors operated by fluid pressure.

, Present vacuum and velocity governors are of low cost because a separate engine drive is not required. Also theinstallation may be made simply by placing the governor between the carburetor and the intake manifold, or they may be so installed as to operate the carburetor throttle directly. However, they inherently cause a power loss when the engine is being governed, and they cause the engine speed to vary considerably when the load is varied from no-load to full-load at the governed speed. I

Governors that utilize engine-driven elements presently control the speed more closely than vacuum and velocity governors with considerably less power loss. However, this type of governor is more costly because a special engine speed-driven element is required which must be connected to the governor throttle by suitable means. Also isochronous operation is inherently impossible with direct engine driven mechanical centrifugal governors without a correcting mechanism.

One of the objects of the present invention is to pro-' Another object of the present invention is to provide an improved governor of the foregoing nature, in which the governor throttle controlling forces are produced without the aid of rotating parts or elements positively driven by the engine, and which, therefore, can be installed in an engine in a simple and easy manner.

A further object of the present invention is to provide an improved governor for internal combustion engines, which, while being operable by forces produced as a result of the flow of air in the intake passage of the engine, eliminates objectionable variations from the preselected or governed engine speed and maintains such speed more uniform than it has been heretofore considered possible with the use of the governors of this general nature.

A still further object of the present invention is to provide an improved governor for internal combustion engines, which governor does not decrease the maximum power that can be developed by the engine in the operation range of speeds below the preselected or governed speed.

A still further object of the present invention is to provide an improved governor for internal combustion engines which governor responds to changes in conditions of engine operation without appreciable time-lag;

atent ice 2 speed following acceleration, which overrun produces, in turn, undesirable kick or lurch on the vehicle operator.

A still further object of the present invention is to provide an improved governor for internal combustion engines, having a throttle or a similar engine-controlling member, in which governor there is produced due to the pumping action of the engine a zone of decreased pres-' sure (i. e. partial vacuum) varying substantially as a function of the speed of the engine at fixed throttle positions and which is utilized for the purpose of controlling the position of the governor throttle, means being pro-- vided to compensate for the variations in the above men tioned decreased pressure (or vacuum) by the changes in positions of the throttle.

Av still further object of the present invention is to provide an improved governor for internal combustion engines, having a governor throttle of substantially the balanced type, improved means being provided to actuate said throttle, which means are of the pressure-responsive type and expose to the action of pressure sufficiently large areas in order to produce ample forces and thus to insure proper operation of the governor mechanisms.

A still further object of the present invention is to provide improved pressure-responsive means for actuat-.

ing the throttle of an engine governor, which means are exposed on both sides thereof to the action'of modifiedv manifold vacuum, the effect of suchmodifiedmanifoldvacuum on'the respective sides of said means beingpcon: trolled by the manifold vacuum to produce the desired; difference of pressures on said means, and thus to cause: movement of said means for actuating the governor throttle.

A still further object of the present invention is to; provide an improved governor for internal combustion engines, said governor having a throttle and a pressure-. responsive diaphragm for actuating said throttle, said diaphragm being subjected at least on one-side-thereof to pressure dependent on manifold vacuum, the effect of. said pressure being amplified by the operation of valve means responsive at fixed throttle positions to said vacuum to produce a more pronounced action on the diaphragm. I

A still further object of the presentinvention is to provide a governor specified in the preceding paragraph, the effect of said valve means being controlled functionally by positions of said valve means. I

A still further object of the present invention is to provide an improved valve for controlling the amplifying means specified in the two preceding paragraphs, and an improved suspension for said valve, whereby substantially instantaneous response of the valve to. variations ofmanifold vacuum at fixed throttle positions is attained not only for ideal or laboratory operation conditions of the engine, but for severe conditions of practical use of the governor, such as are encountered in a motor vehicle on; the road under all weather conditions. I

A still further object of the present invention .is to provide an improved governor or controlling device including valve means, said device requiring for itsproper operation substantially instantaneous response of the. valve means, said valve means being suspendedv to insuresubstantially frictionless movements of the valve within the range of operational travel of its flow controlling body and/or its supports. i

A still further object of the present invention is to; provide an improved governor or a controlling device in cluding valve means required to give substantially instantaneous response, said means being suspended on .a support arranged outside of the path of the controlled medium, whereby adverse effects of the medium on resistance to movement of the valve in its supports is greatly decreased.

One object of the present invention is to provide a governor for an internal combustion engine which is simple and of low cost since an engine speed-driven element is not required, and which provides better performance than present-day velocity and engine driven. governors. There is substantially no loss in R. P. M. when the engine is loaded, and there is no power loss because the governor throttle remains wide open until the governed speed is attained.

Conventional velocity governors that incorporate an offset or unbalanced throttle valve cannot govern a gasoline engine at engine speeds above the speed corresponding to maximum power without causing excessive power loss. Another object of my invention is to provide a vacuum governor that will govern at an engine R. P. M. higher than the R. P. M. corresponding to peak power.

Present velocity governors with offset throttles permit the drivers of vehicles equipped with these governors to cheat, or to operate the engine at speeds above the governed speed. So-called anti-cheating devices are required in these governors to compensate for this inherent tendency. Another object of my invention is to provide a vacuum governor that inherently has no tendency to cheat.

All governors at the present time are considered to be dangerous in traflic emergencies because the engine cannot be operated above the governed speed to avoid a serious accident if necessary. Another object of my invention is to provide a governor that includes means whereby the governor can be released by the driver while driving, to cause the governor throttle to snap to the wide-open position instantly.

For automotive opertion, iscchronous governor performance is desired, or Zero change in R. P. M. when the load is varied from full-load to no-load. Present velocity and vacuum governors have a variation of from 350 to 500 R. P. M. when the load is varied from fullload to no-load. Also, as will be shown, governors that incorporate centrifugal elements to control directly the throttle valve inherently cannot give isochronous operation without adding correcting means. Another object of the present invention is to provide a governor inherently capable of giving isochronous operation at all governed engine speeds.

Another object of this invention is to provide novel means for compensating for the undesirable variation of engine vacuum with change in throttle position, so that the desirable variation in engine vacuum with change in engine speed is available to control the governor.

' Present velocity governors utilize the restricting eifect of an off-set throttle valve so that the air-forces cause the throttle to move against a spring resulting in an inherent loss of power. A further object of this invention is to provide a vacuum governor having a power operated throttle valve so that the air-forces of the engine are not used to operate the throttle thereby preventing a power loss from this cause.

Still another object of the present invention is to provide novel means for adjusting the governor for governing the engine at selectively different engine speeds.

These and other objects which will appear more clearly as the specification proceeds, are accomplished, according to the present invention, by the arrangement and combination of elements set forth in the following detailed description, defined in the appended claims and illustratively exemplified in the accompanying drawings, in which:

Figure 1 is a schematic view, partly in elevation and partly in section, showing one form of my governor operatively related to a carburetor and engine manifold or intake, and which uses the manifold suction as the controlling force,

Fig. 2 is an oblique drawing of an important detail of the preferred form of my invention,

Fig. 3 is a chart showing the actual variation of manifold vacuum with engine speed at various fixed-throttle positions,

ig. 4 is a chart showing the characteristic performance of conventional governors and the improved performance of the present invention,

Fig. 5 is a plan view of one method of providing an adjustment in the governor so that the engine can be governed at different speeds,

Fig. 6 is a diagrammatic representation, partly in elevation and partly in section of another form of my invention adapted to be intercalated between the carburetor and the engine intake manifold, as in Fig. 1,

Fig. 7 is a schematic drawing showing how the powercontrol unit of Fig. 1 can be varied so that a non-compressible fluid such as engine oil, for example, may be used to power the governor throttle instead of engine vacuum.

The governor of the present invention is shown as a sandwich type governor in this disclosure but may be combined with the carburetor if desired to operate the carburetor throttle. In the form shown in this disclosure, the manifold vacuum is used as the controlling force of the governor, or the brain force.

The important fundamental principle of this governor depends on the fact that the manifold vacuum may be varied by means of two factors, and hence is comprised of two components as follows:

1. The manifold vacuum may be varied by changing the throttle position at constant R. P. M.; hence the manifold vacuum is responsive to changes in throttle position, the vacuum increasing as the throttle opening decreases. This component may be referred to as throttle vacuum.

2. The manifold vacuum may be varied by changing the engine R. P. M. at any fixed-throttle position; hence the manifold vacuum is also responsive to changes in engine speed, the vacuum increasing as the engine speed increases. This component may be referred to as speed vacuum.

In the present invention, means are provided substantially to eliminate or compensate for the undesirable variation of manifold vacuum with throttle position (throttle vacuum), and to utilize the important vacuum that varies consistently with engine speed at any fixedthrottle position (speed vacuum).

The governor of the present invention may be divided for convenience into two units. One unit is what I prefer to call the brain-unit which, according to the present invention, is incorporated to compensate for the change in engine vacuum with throttle position (throttle vacuum) and to utilize the change in vacuum with change in engine speed (speed vacuum) as the controlling force. The throttle vacuum may be best compensated for by means operable by the throttle. The second unit consists of the mechanism provided for actuating the governor throttle positively in accordance with changes in the aforementioned controlling vacuum, and for convenience herein is termed power unit. The brain unit, therefore, controls the power unit in a manner that will be explained.

It also should be understood that regardless of whether the term, suction or vacuum is used instead of piesure, it is to be interpreted as the difference between two absolute pressures, and accordingly refers to the same physical state as when the term, pressure is used. A through discussion of suction and absolute pressure is set forth in my book, Aircraft Carburetion, pages 6-27, published in 1946 by John Wiley & Sons, New York.

It should be understood that several forms may be in corporated to provide the desired brain-unit" according to the present invention; hence the brain-units shown in the accompanying figures are meant to be exemplary.

likewise, several forms of the power unit" may be conr. bined with the brain-unit to produce the present raven tion so that the power units shown in the accompanying figures are merely illustrative.

Briefly one form of the brain-unit comprises a chamber which is exposed to the engine vacuum, or a function thereof, and is enclosed onopposite'ends'by displaceable members that seal the chamber, whereas resilient means tend to hold the two displaceable members apart in opposition to the force of themanifold vacuum. One of the two displaceable members moves as a consistent function of throttle movement, whereasthe other displaceable member in the preferred calibration of the form shown in Fig. 6, for example, moves substantially, but not exactly, as a function of engine speed to'move the controlling element of the powerunit.

The brain-unit as above noted, preferably has a diaphragm disc or plate for the displaceable member that operates the power unit, see Figs. 1, 6, and a piston for the displaceable member that moves in accordance with changes in the throttle position,- see Figs. 1, 6.

The power-mechanism comprises a displaceable member which is suitably connected to actuate the governor throttle valve. The displaceable member divides its housing into two separate chambers, and the pressure in one or both of these chambers is controlled by valving means which is moved by a movable member operable by a function of the manifold vacuum or brain pressure.

The displaceable member of the power mechanism for.

operatin the throttle valve forms two pressure chambers and may be of any suitable type such as a diaphragm, piston, or swingable vane type. The diaphragm type is preferred and is shown in this disclosure by way of illus tration although thelatter type is shown in my co-pending application, Serial No. 14,282. In one arrangement the pressures in both chambers'formed by. the displaceable member are regulated by suitable valving means operable by the brain-unit, see Fig. 1. However, in another form of my invention, the pressure in only one'of these chambers is controlled by the valvemeans, and resilient means is used to oppose this pressure, see Fig. 6. The valving means for controlling the pressures in the chambers formed by the displaceable member in its housing may be of several types as disclosed in my co-pending application, Serial No. 14,282, now Patent No. 2,661,728 issued December 8, 1953. The preferred form is shown in this disclosure which is apoppet-type of valving means suspended in space'bythin leaf springs, seeFigs. 1, 2, 6, 7. When referring to an orifice in this disclosure, it should be understood that regardless of whether the'word jet, orifice, or restriction is used, they all refer to a controlled or designed restriction or opening in a fluid flow circuit for the purpose of providing a controlled change in pressure in the fluid flow circuit.

Referring now to the figures, and specifically to Fig. 1, a governor housing 1 is shown as a sandwich type positioned between and sealed to the downdraft carburetor 2 and the intake manifold 3 of what maybe considered as a conventional type of internal combustion engine, the manifold 3 being employed to direct the charge from the carburetor 2 to the various cylinders of the engine. In Fig. 1 by way of illustration, a downdraft carburetor is shown. However, the governor may be used with either an updraft or downdraft carburetor. The sandwic governor includes a separate governor throttle 4 in addition to the conventional carburetor throttle 5 whichis located on the downstream side of the carburetor venturi 6 as shown. The governor throttle 4 controls the engine only when the carburetor throttle 5 is opened sufliciently to allow the engine to exceed the governed R. P. M.

In Fig. 1 the air entering the carburetor flows downward through the venturi as shown bythe arrow. Fuel is admitted to the air at the venturi throat beforethe air reaches the throttle 5. The mixture then flows downward past the throttles 5 and 4 and into the intake manifold 3 where the mixture is distributed to the various cylinders, all in a manner well known to those skilled in the art. V

' Now consider the brain-unit shown in Fig. 1. ,This unit comprises the cam 7 which is secured to the throttle shaft 8, the piston 9 slidable in the cylinder'10, the

spring 11, and the diaphragm 12; the diaphragm 12 joins the brain-unit to the power unit and hence may be considered as part of both units. In the form shown in Fig. 1, the cam 7 actuates the piston 9 by means of the screw 9 which is secured to the piston 9 by the nut 9.. The head or cam follower 9 of the screw 9 is rounded as shown so that the piston is readily moved by the cam. The piston 9 is held against the cam 7 by means of the leaf springs 35 and 36 in a manner that will be explained.

The chamber 13 which is formed by the piston 9 and diaphragm 12, is exposed to the manifold vacuum through the passage 13 and 14. The restriction 15 has no effect during normal operation since the chamber 13 is completely closed so that no air can flow through the restriction. The passage 16 is closed by the release unit 17 which will be discussed in a later section. For the present, therefore, the passage 16 and restriction 15 may be considered omitted.

Next consider the power unit shown in Fig.- 1. As shown in Fig. 1, the governor throttle 4 is actuated by a fluid motor comprising the two variable fluid chambers 18 and 19 which are formed by the power diaphragm 20 in relation to the walls of the casing 21, the sealing diaphragm 22, the shaft 23, and the arm24 which imparts angular motion to the throttle shaft 8 so that the throttle valve 4 is operable by the diaphragm 20. The intake manifold suction is used as a source of power to actuate the diaphragm 20. The brain diaphragm 12 is actuated by the portion of manifold vacuum in chamber 13 that changes substantially with engine speed, and the diaphragm 12 actuates the valve-piece 25 which contains four poppet-type variable restrictions which are used to control the pressures in chambers 18 and 19 in the following manner.

The principle of the power unit is that fluid is circulated through each of the two chambers 18 and 19 or extensions thereof, which are formed by the diaphragm 20. In this respect it will be appreciated that it makes no difference whether this circulation occurs directly in the chambers 18 and 19, or in some passage orchamber in open communication therewith. In the examples shown, no circulation actually occurs in the chambers 18 or 19, or their equivalents, but rather .in passages or chambers to which they are in open communication. Each of the chambers has inlet and outlet restrictions in the circuit therethrough. The resistance of one. or more of the restrictions is caused to vary by a change in position'of the brain diaphragm when the R. P. M. changes from the governed speed so that the pressure in one chamber changes with respect to the pressure in the other chamber and the diaphragm 20 moves the throttle 4 until the original governed speed is restored. The bel-. lows seal 22 seals the vacuum in chamber 18, the pressure on the other side of the bellows in chamber.22 being atmospheric because of the communication. of chamber 22' with the atmosphere through conduit 22?.

Referring to Fig. 1, the manifold vacuum causes air to circulate through each ofthe two fluid-bleed circuits in the chambers formed by the diaphragm 20, or extensions thereof. In the fluid-bleed circuit for circulating fluid through an extension of chamber 18, atmospheric air is caused to flow through air filter 26 which is the inlet end or port, through conduit 27, through the inlet variable restriction 28, through the extension 29 of chamber 18, through the outlet variable restriction 30, through the manifold vacuum conduit 31, and to the intake manifold through the outlet end or port 14. In

the fluid-bleed circuit for circulating fluid through an extension of chamber 19, atmospheric air is caused to flow through the air filter 26 and conduit 32, through the inlet variable restriction 33, through the extension 34 of chamber 19, through the outlet variable restriction 35, through the manifold vacuum conduit 31., and to the intake manifold through the outlet end or port The amount of air that flows through these two air-bleed circuits is very small since it is used merely for pressure control. This control unit is an application of H16 bleedprinciple of pressure control described on 3 and 35 of my said book, Aircraft Carburetion.

Thus, the four valves of the valve-piece serve as four variable orifices or restrictions associated with the two fluid-bleed circuits directed through the chambers formed by the diaphragm 28. In the preferr form, the four valves are of the conical poppet-type, as shown, and are arranged on the valve-piece so that when valves 28 and 35 gradually close, the valves 3% and 33 simultaneously open gradually. Fig. 1 is suspended by the two flat leaf springs 35 and 36 of low rate which are secured to the supports 37 and 38, respectively, by any suitable fastening means, such as by rivets as illustrated. Thus the main function of the leaf springs is to hold the valve-piece in position, the support afforded thereby restricts the motion of the valve-piece to substantially an axial direction and the permitted swinging motion is substantially frictionless. It will be apparent that other substantially frictionless swingable supporting means may be used in which no spring force is involved. With this preferred construction, the valve-piece has no sliding metal-to-metal contact and therefore is frictionless and is free from the efiects of dirt, gum, or rust, so that this governor responds substantially instantaneously to the slightest change in load to maintain the governed speed. The slight are produced by the travel of the leaf springs is negligible in view of the length of the leaf springs compared to the very short travel of the valve-piece. Fig. 2 is an oblique view showing the leaf spring 35 the left end of the valve-piece 25, and the riveted support 37. The spring 35S has a hole that permits the shaft of the valve-piece 25 to slip through with substantially no clearance. The springs 35 and 36 when free are bent so that when they are installed as shown by Fig. 1, they apply a slight force on the valve-piece tending to move it to the right. Thus the springs 35 and 36 always hear a slight force on the abutments 39 and 4t respectively, of the valve-piece 25 tending to move it to the right.

The valve-piece 25 is urged to the left by the force of the spring 11. The force of the leaf springs is very small compared to the force of the spring 11 so that the brain diaphragm 12 and the valve-piece 25 can be forced to the left by the force of the spring 11 when required. The full manifold vacuum is transferred into chamber 13 through conduits 14 and 13 so that the force of the spring 11 is opposed by this vacuum, there being atmospheric pressure on the opposite side of the diaphragm 12, that is, in chamber 41 which is in communication with air inlet 26.

When the valve-piece 25 moves to the right because of an increase in speed-vacuum in chamber 13, the opening of the restriction 28 increases and the opening of the restriction 30 decreases; the effect of this action on the air-bleed circuit through chamber 18 is to reduce the amount of vacuum which is transferred into chamber 13 so that the absolute pressure in chamber 13 gradually increases when the valve-piece moves to the right. Also when the valve-piece moves to the right, the opening of the restriction increases, and the opening of the restriction 33 decreases; the effect of this action on the air bleed through chamber 19 is that it increases the amount of vacuum which is transferred into chamber 19 so that the absolute pressure in chamber 19 gradually decreases.

The valve-piece shown in Hence, when the valve-piece moves to the right, the pressure differential existing across the diaphragm 20 increases to cause the governor throttle 4 to be moved by the diaphragm 20 toward the closed position.

Conversely, when the valve-piece 25 moves to the left, the pressure differential existing across the power diaphragm 20 increases to cause the governor throttle 4 to be moved by the diaphragm toward the open position.

It is apparent that to prevent the throttle from moving when the governor is on-speed, the pressure in chamber 15 must be substantially equal to the pressure in chamber 18, and the valve-piece 25 must be substantially at rest in a stable position. When the valve-piece comes to rest, all four of the restrictions are about one-half open, so that air continuously bleeds through the two fluid-bleed circuits in the chambers formed by the diaphragm 2% when the governor is on-speed, or stabilized. At this time the absolute pressure in chamber 18 is then about equal to the absolute pressure in chamber 19. Actually, the pressure in chamber 18 will be slightly higher than in chamber 19 because of the slight unbalancing effect of the seal 22.

As a result of the air bleed circuits, the slightest movement of the valve-piece 25 in either direction substantially instantaneously changes the pressures in each chamber in the opposite direction. This last feature of providing a continuous bleed of air through each chamber while the governor is at settled speed in combination with the substantially frictionless swingable valve suspension is one of the novel features of the powenunit and explains why this governor responds substantially instantaneously to change in engine speed; when the diaphragm 12 moves the slightest amount in either direction as a result of a change in engine speed, the two fluid-bleeds are affected oppositely, so that the pressure in one of the chambers formed by the diaphragm starts to increase while the pressure in the other chamber starts to decrease; thus the throttle valve 4 is moved substantially instantaneously to restore the governed speed of the engine. The total travel of the valve-piece is very slight so that the governor throttle responds substantially in stantaneously to the slightest change in speed.

It is important to understand that, in the preferred forms of my invention shown in Figs. 1 and 6, manifold vacuum is used merely as a source of power to actuate the power diaphragm 20; it cannot be said that the movement of the power diaphragm varies in accordance with changes in the manifold vacuum, nor is it responsive directly to the vacuum in the manifold, because the diaphragm moves primarily when the valve-piece 25 is moved during all governor operating conditions; hence, the power diaphragm is responsive substantially only to the movement of the valve-piece 25. Also, as shown in Fig. 7, a fluid whose pressure is entirely independent of the pressure in the manifold may be used to power the diaphragm 20 with equivalent results, proving further that the movement of the power diaphragm is not operable by the pressures in the intake manifold in the forms shown.

In Fig. l, the very small orifice 42 allows a very slight amount of gasoline vapor to flow through conduits 43 and 34 and out through the variable restriction 35 and conduits 31 and 14. Also, the very small orifice 44 allows a very slight amount of gasoline vapor to flow through conduits 45 and 29 and out through the variable restriction 3t and conduits 31 and 14. This gasoline vapor provides a washing action that tends to clean continously the variable restrictions of the valve-piece 25. The restrictions 42 and 44 and the conduits 43 and 45 may be omitted if desired.

Before discussing the operation of the entire governor as a unit, observe the curves shown in Fig. 3. This is a chart showing the actual curves of engine manifold vacuum vs. engine speed at various fixed throttle positions for a 1947 Chevrolet passenger car engine, and is intended to .be representative of such curves for all gasoline engines. Observe that at each fixed-throttle position such as 19 degrees, for example, the manifold vacuum varies consistently with engine speed; in the example mentioned at 19 degrees of throttle opening the vacuum varies along thecurve A-B from 2.5 inches of mercury at 1000 R. P. M. to 11.3 inches of mercury at 3500 R. P. M. merely'due to the change in engine pumping action at thedifierent engine speeds and represents speed vacuum. At other fixed throttle positions the vacuum again varies with speed except the amount of vacuum at each speed is difierent. For example, at the lower throttle opening of 15 degrees, the vacuum varies along the curve C-D from 4.5 inches of mercury at 1000 R. P. M. to 15.3 inches of mercury at 3500 R. P. M. showing that although the vacuum varies consistently with engine R. P. M., the vacuum at each R. P. M. is higher at lower-throttle openings which represents throttle vacuum. Thisis true because at lower throttle openin'gs at the same speed, the throttle offers more resistence to the flow of air to the engine. The brain-unit compensates for this undesirable variation of vacuum-at difierent throttle openings at a fixed R. P. M. (throttle vacuum), so that the power unit is responsive primarily only to the variation of vacuum with change in engine speeds (speed vacuum) along the fixed-throttle curves such as AB and -D.

"Now consider the operation of the governor when the brain and power units, examples of which have been described, are combined to form the present invention. Briefly the overall governor operation is as follows: Forces which vary substantially with the engine speed, or speed vacuum, control a power amplifying mechanism that operates the governor throttle so that when the engine speed increases above the governed value, the governor throttle is closed sufiiciently to cause'the en-' gine speed'to reduce to its original value; and when the engine speed decreases below the governed value, the governor throttle is opened sufiiciently to cause the engine R. P. M. to increase and return to the original governed speed regardless of load.

IniFig. 1 it is obvious that if the valve-piece 25 were actuated by centrifugal means, it would move in accordance with the speed of the engine. Then the valvepiece would efiect a corresponding but greatly amplified movement of the throttle 4 also in accordance with the speed of the engine in a manner previously described; Governors of this type in which the throttle movement is regulated by the speed of the engine give excellent performance becauseithe movement of the throttle is independent of changes in load, or more specifically, changes in manifoldvacuum accompanying a change in throttle position. T

Similarly, in the governor of the present invention, the valve movement and hence the throttle movement may be made to vary generally in accordance with the speed of the engine. This result may be accomplished by the brain-unit which in general prevents the variation in engine-load, or throttle-vacuum, from having any undesirable effect on the positioning of the valve-piece.

Consider an engine operating at a constant R. P. M.;

when the load is decreased and the throttle opening reduces at this constant speed, the vacuum in chamber 13, Fig. 1, increases only due to the throttle closure (throttlevacuum). Since the valve movement is to be unaffected by this vacuum change, something must be done to offset or compensate for this added vacuum on the diaphragm 12 as the load is reduced. This purpose is instantly accomplished by the opposing force of the spring 11 which is varied in accordance with the throttle-movement by means of the piston 9 and the throttle-actuatedcam 7; the closure of the throttle eifects a compression of the spring whereby the spring-force on the diaphragm 12 is increased exactly enough to compensate for the increase-in throttle' vacuum at the correspondingly-lower thrqttlegpenjng. Ihe contour of the cam ;7 is made so that at each throttle position the force of the spring 11 exactly balances the force on, the diaphragm due to the vacuumin, chamber 13 corresponding to the said throttle position. Then at any fixed throttle position, when the load is reducedaso that. the. engine speed starts to in crease, theyacutim in chamber 13 increases only because. of. the increased pumping efiect of the engine (speed-vacuum).whereby the valve-piece 25 is moved to the right only .duefto the change in engine speed. The movement oiithe valve-piece to the right causes the throttle ,opening, to reduce to a new position to maintain fthe,.sa me. governed R. P. M. Again at this new position, .the' change in cam contour eifects an increase in theflforce of the spring. 11 to oifset the increase in throttlervacuum? accompanying the latter change in throttle opening in-a manner explained above. Then the corresponding reduction in throttle opening reduces the enginespeedto theoriginalyalue whereby the governor is stabili zed.. at-.the new governed R. P. M. Thus it can now be seen that the cam may be calibrated so that the valve-piece. moves in. accordance with the engine speed, or morespecifically, speed-vacuum, independent of changes in load or throttle position.

The changein springforce due to the very short movement of the valve-piece with change in R. P. M. is negligiblein comparison .to the large change in spring force due .to throttle movement; hence the throttle movement in. effect provides .different spring forces at various loads whereas thespringforcechange is very slight within the small travel .of the valve-piece.

'Referringt-to. Eigs. 1 and.v3,,consider the governor in stableoperationfat a fixed governed speed so that the throttle is in afixedposition at 24 degrees at 2000 R. P. M., for example, which. is shownat point B in Fig. 3 at 5 inches of mercury..-. Atv this stable fixed-throttle position, the cam 7 maintains the piston 9 in a definite position as determined by the contour of the cam. When the engine descends a hill, the ReP. M. tends to increase causing the vacuum in chamber13- to increase from E along the curve G-H, .see. Fig. 3,- toward H. The increase in vacuum with R. P. M., or speed vacuum, causes the diaphragm 12 and valve-piece 25 to move to the right so thatthe power diaphragm 20 starts to move the throttle 4 towards a closed position. When the throttle opening decreases, the engine vacuum increases considerably just due to the change in throttle position as explained above which would cause the throttle to be shut tightly if not corrected for. The efiect of this undesirable change in vacuum (throttle vacuum) on the diaphragm 12 is compensated for by the fact that when the throttle opening decreases, the piston 9 is moved to the left by the cam 7, therebyin efr'ect compressing the spring 11 so that its increasedresisting force substantially cancels the effect of the increase in vacuum due to the change in throttle opening on the brain diaphragm 12; then the brain diaphragm continues tobe responsive primarily to the change in vacuum due to changes in engine speed regardless of throttle position. In this example, the throttle will continue to close until the engine speed reduces to its original'value of 2000 R. P. M. and the throttle opening has reduced to 19 degrees on curve A-B, Fig. 3 atF. At this new position at the new load the governor is stable because the vacuum which is in chamber 13 corresponding to 2000 R'. P. M. at 19 degrees throttle openingnow exactly balances-the force of the spring 11 that corresponds to 19 degrees throttle opening so that the valve-piece .25"iand hence the throttle 4 are stable. At this condition, the vacuum has increased to 7.1 inches of mercury at F which exactly balances the new force of the spring 11 at 2000 R. P. M. If the R. P. M. were above or below this value at this same throttle opening, the vacuum would vary correspondingly along the curve A-"--B and the'governor would not be in a stable position so "that itwould "seek anew stable throttle opening elsewhere. A slight increase in speed due to a decrease in load will cause the vacuum to increase slightly from F along the new curve A-B towards P at this new fixed throttle opening of 19 degrees so that the governor becomes unstable and the valve-piece again moves to the right which causes the throttle to seek a new stable position at a still smaller opening which will maintain the engine at 2000 R. P. M. Assume that the new stable throttle opening is degrees as shown at R on the curve C-D where the new increased vacuum is 11.6 inches of mercury. This vacuum corresponds to a throttle opening of 15 degrees at 2000 R. P. M. and the force of the spring 11 has been increased by the movement of the throttle from 19 degrees to 15 degrees to balance exactly the new higher vacuum at R; and since the throttle has been carried to a lesser position, the vacuum caused by an increase in speed above 2000 R. P. M. has been eliminated so that the governor is stable.

Assume that when the speed increased at 19 degrees throttle opening, it reached a speed corresponding to P on curve AB which, of course, is exaggerated since the governor would respond long before this speed is attained. Then assume that when the throttle reduced to 15 degrees the R. P. M. only reduced to a value corresponding to S which is still higher than 2000 R. P. M. it has been shown that at 15 degrees throttle opening, the force of the spring 11 will exactly balance a force corresponding to 11.6 inches of mercury at R. However, the vacuum in chamber 13 at 15 degrees is now 12 inches of mercury at S so that the governor is still unstable and the valveiece continues to move to the right causing the throttle opening to decrease until the effect of the vacuum due to the increase of R. P. M. above the calibrated governed speed is eliminated. Assume that the final stable position is at M on the curve X-Y corresponding to 11.2 degrees of throttle opening. At this stable position, the vacuum is 14.1 inches of mercury at M which exactly balances the new higher spring force as determined by the cam 7 at 2000 R. P. M. at 11.2 degrees of throttle opening. Since the change in vacuum due to R. P. M. has been eliminated by the closure'of the throttle which reduced the R. P. M. to 2000, the governor is now stable.

Thus, from the initial stable position at E to the final stable position at M at the lower load, the throttle vacuum at the same R. P. M. has risen from 5 inches of mercury at E to 14.1 inches of mercury at M merely due to h e increase of the restricting effect of the throttle 4 as the opening reduced from 24 degrees to 11.2 degrees. To compensate for this increase in vacuum, in efiect the contour of the cam 7 caused the spring 11 to be compressed just enough to position the valve-piece so that the diaphragm 20 and the governor throttle 4 are stable at 11.2 degrees of throttle opening. Any increase or decrease in R. P. M. from 2000 R. P. M. at this stable condition will cause the governor to become unstable and seek new stable position, which, according to the contour of cam 7, will always be at a speed of 2000 R. P. M. If a higher engine speed is required, another cam contour may be worked out corresponding to the higher speed. Obviously, all points on the new cam would be radially larger at a high speed, and smaller for a lower speed.

When the load is increased by ascending a hill for exale, the governor functions exactly in reverse of the pie shown above to restore the governed speed. For r the governor stable at M on curve i P. M. and the vehicle ascends a slight tnet this load causes the R. P. M. to re- .ggxatcd conditions at N. Now the vacuum has reduc -i11 l4.l inches of mercury at M to 13.7 incnes of mercury at N causing the valve-piece to be moved to the left by the spring 11 so that the throttle opening increases to the new stable position .t R on curve C-D. At this new position the R. P. M. has returned to 2000 and is; e force of the spring 11 has been reduced by hill. duct: to the the change in position of the cam 7 to balance exactly the force corresponding to the vacuum at R, or 11.6 inches mercury. When the load is reduced further, the governor maintains a stable condition in the same manner.

in actual operation, this entire stabilizing action occurs almost instantaneously so that at all loads at 2000 R. P. M., the engine speed will not vary more than 5-10 R. P. M. from the governed speed if the cam 7 is correctly calibrated Also, in actual operation, the effective area of the diaphragm 12 substantially equals the exposed area of the piston 9 so that the vacuum in chamber 13 is the force that causes the spring 11 to be compressed and expanded instead of the force of the cam 7. Therefore the vacuum on the diaphrgam 12 does not cause the piston to move to the right against the cam. The result is identical with the assumed condition, and the purpose is to cause the piston to follow the cam 7 with a minimum resisting force. If the piston were urged against the cam with the full compression of the spring 11 at 20 inches of mercury vacuum, for example, and, if the piston area were much smaller than the diaphragrn area, the force of the cam follower 9 on the cam 7 might be sufiicient to cause diaphragm balancing problems, particularly in the form to be discussed, Fig. 6; also the added force acting on the cam 7 would cause its movement to be retarded causing excessive over-run. if the piston area equals the effective area of the diaphragm 12, there spring ll and the vacuum in chamber 13 produces no force causing the piston to bear on the cam. The only force causing the piston 9 and screwhcad or cam follows 9 to follow the earn 7 is the initial force of the leaf springs 35 and 36 as explained previously. Then the piston will always follow the cam with substantially a constant but small force produced by the leaf springs, or their equivalent. However, in eflect, the throttle movement causes the compression of the spring 11 exactly as though the cam were overcoming the force of spring 111 because the cam follower 9 always follows the contour of the earn 7. in actual operation entirely from a mechanical or physical standpoint, the diaphragm l2, spring ill, piston 9, and cam follower 9 might be considered as a connecting link or a shaft. Considered only in this mechanical or physical aspect, it might be said that the cam 7 acts to position the valve-piece 2 5 by means of a connecting shaft whose length varies with speed-vacuum and throttle-vacuum. Considered in this manner, the valve end of the spring would be sub jected to speed-sensing movements, whereas the cam-end cf the spring would be subjected to movements to compensate for throttle vacuum or load changes.

It is apparent from the foregoing discussion relating to Fig. 1 that the power diaphragm. 20 is responsive substantially to changes in the position of the brain diaphragm 12, and more particularly to the travel of the valve-piece 25 rather than to changes in manifold vacuum. When the manifold vacuum changes a very slight amount, this differential would have little efiect on the power diaphragm 20 even if it were applied directly to chambers 18 and 1%, and were not restricted by the valves of the valve-piece 25, as it actually is; however, the brain diaphragm 12 responds to this small change in vacuum which is applied directly thereon. The slight corresponding movement of the valve piece 12 causes a substantial movement of the power diaphragm 20 because of its sensitive stabilizing action as described above.

The disclosure thus far has implied that it is preferable to calibrate the cam 7 so that the movement of the valve piece 25 and the brain diaphragm 12. varies precisely in accordance with the speed of the engine. Although with the preferred calibration of cam 7, the movement of the valve-piece 25 varies substantially with the speed of the engine, it does not vary exactly in accordance with changes in engine speed, and the reason it does not is one of the outstanding features of my governor since it enables this governor to give isochronous operation. It is impossible for any governor whose throttle varies directly in accordance with the speed of the engine to give isochronous operation without adding correcting means to the governor. This will be shown by reference to Fig. 4 showing the performance of various types of governors now in present use compared to the performance of the governor of the present invention. The chart shows the relation between horsepower on the vertical scale and engine R. P. M. on the horizontal scale. The curve R--C-A-ES represents the power of the engine at wide open throttle at all engine speeds and is the maximum power available at that speed. The line AB represents isochronous governor operation obtainable with my governor, so that the speed in this example is constant at 2300 R. P. M. Thus, the line AB shows that at all loads and throttle positions, the engine speed .is constant from noload at B up to full-load at wide-open-throttle at A.

Consider a governor having centrifugally operated throttle control means such as a flyball governor for'example. In this'class of governors, the throttle position always is the same at a definite speed regardless of load variations. For example, at 2300 R. P. M. one throttle opening is always obtained such as 60 degrees. At 2400 R. P. M. a lower throttle opening such as 30 degrees is always obtained. At 2500 R. P. M. a still lower throttle opening is always obtained such as 15 degrees. And at 2550 R. P. M., a very low throttle opening is always obtained such as 7 degrees. Thus, the performance curve for this governor would appear as AM in Fig. 4 where the throttle is Wide open at 2300 R. P. M. and is at low-load at 2550 R. P. M. so that the governor requires 250R. P. M. to unload from A to M. centrifugally controlled governors such as this can be set to load and unload in 100 R. P. M. without excessive instability under certain conditions. However, if they are set to load in less than 100 R. P. M., they approach an unstable condition, which can be understood by considering such a governor at the extreme condition of zero speed variation, or isochronism. At this condition, the engine speed must be the same at all loads. As shown above, governors whose throttles are controlled in accordance with changes in the speed of the engine always have one definite throttle opening at any one speed so that at constant R. P. M. only one throttle opening would be available for all loads from full-load at A to no-load at B, see Fig. 4; however, different throttle openings are required at different'loads to produce isochronous operation so that. with centrifugally controlled governors isochronous operation obviously is impossible without additional correction de vices. The governor would be extremely unstable and could not be used in operation.

If the cam contour were calibrated to compensate exactly for the change in throttle-vacuum at the governed speed, then the travel of the valve-piece would be responsive only to engine speed. In the power unit of the form of my invention illustrated in Fig. 1 the valvepiece always returns to a substantially neutral position in order to stabilize the governor because the throttle 4 is actuated freely by only the diaphragm 20 as previously explained. Since the valve-piece can only be in one neutral position, and can only be in this one position at one speed, the governor is substantially isochronous if the cam contour is calibrated to compensate completely for the variation in throttle-vacuum. However, if it is desired to produce a speed-droop as shown by the curve AM, Fig. 4, then the cam may be calibrated with progressively larger radii as the throttle closes whereby excess vacuum must be applied to the diaphragm 12 to stabilize the governor, whereas this excess vacuum is produced only at a progressively higher engine speed as the load is reduced. Hence, although the power unit in the governor illustrated in Fig. 1 would produce isochronous operation if actuated by speed controlled means, the load compensating mechanism may be used.tov regulate thepb: sition of. the valve-piece to provide'any desired .?speeddroop.

Present-day vacuum .and velocity. governors prevent the engine from obtaining themaximum.wideropen-throu tle power because of their offset..thr,ottlesand.theyalso cause the engine speed to .vary considerably as the.,l0,ad is .variedbetween full-load and noL-load; a. typical curve for a conventional velocity or vacuum governor is shown by the line CKH, Fig. 4, in which the engine speed. will vary 500 R. P. M. or more when the engine load varies from full-load to no-loadat thegoverned speed. The power .loss is shown as the diiterence in horsepower at compared to A, Fig. 4. Since my governor has a poweredand substantially balanced throttle 4, it can operate along the curve AB; there. is. no power loss and no R. PPM. loss so that the performance is far superior to other vacuum or velocity governors as well as being superior to speed-controlled governors as explained above. Also velocity governors do not give good control at low engine speeds, such as 1400R. P. M., and cannot govern at speeds above the speed giving the peak horsepower of the .engine without extreme power loss. Because the vacuum vs. R. P. M. curves, Fig; 3, have a steep slope at low engine speeds and the throttle of thepresent invention is power-operated by a servo-mechanism during all governor operating conditions in accordance with these curves, the governor of the present invention will give isochronous operation at very low speeds as shown at 1400. R. P. M. by thecurve CD, Fig. 4. [For the same reason the governor of the present invention will give isochronous operation at speeds above the speed corresponding to point N which is the power peak; this operation is shown, for example,.bythe curve E-F at 3200 R. P. M., Fig. 4. y

Many accidents could be avoided if the driver could operate his vehicle above the governed speed in certain traffic emergencies. Novel means are provided in the present invention to permit the driver of automotive vehicles to release the governor in emergency while driving, so that the engine may be operated above the governed speed to avoid an accident. Referring to Fig. 1, this result is accomplished by means of the governor release 17. A hollow chamber 46 is formed. in the cup-shaped piece 47. The opening of the piece 47 is closed and sealed by the thin lead or tin disc 48. The ring 49 and shield 50. are secured to the lead disc as shown. Thecup-shaped piece 47 may be mounted on the instrument panel or steering-column within easy reach of the drivers hand. Chamber 46 communicates with chamber 13 in thegovernor by means of the conduits 16 and 16 which extends through the firewall of the engine so the governor release unit 17 may be installed in the driver's compartment. When the governor release is installed, the restriction 15 is installed in the governor passage 13. The release operates as follows: When the lead disc 48 is not broken, the full manifold vacuum is transferred into chambers 13 and 46 through conduits 13 16 and 16*. Since a static condition exists, the restriction 15 has no effect on the operation and the governor functions normally. When the ring 49 is pulled, the lead seal 48 is broken so passages 16 and 16 are in open communication with the atmosphere so that air circulates through these passages into chamber 13, through the restriction 15, and out the conduit 14. The effect of the restriction 15 is to lower the vacuum in chamber 13 at all conditions sufficiently to cause the valve-piece 25 to move instantly to the left thereby causing the throttle 4 to be opened instantly and to remain open. When the vehicle is returned to its garage, a new seal is installed and the governor will operate normally. The supervisor of a fleet of trucks, for example, keeps a record of the broken seals of each driver, and the drivers are allowed a definite number of broken seals per year before being penaliZed. If the governor release unit 17 is omitted, the line 16 and the restriction 15 may be omitted. The shield St) protects the soft lead disc 48 from being punched by nails or wires, rendering the governor tamperproof. Also, if preferred, the release unit may be installed on the governor body 1 and a piece of long wire will connect the ring 49 with another ring mounted in the drivers compartment. The driver then pulls the wire to release the governor which breaks the seal 49. This arrangement has the advantage of eliminating the long external conduit 16 and 16 Fig. 5 shows one method for adjusting the various governed speeds so the governor can operate along selectively different curves such as C--D at 1490 R. P. M., at 2300 R. P. M., or E--F at 3280 R. P. M., Fig. 4, for example. Referring to Fig. 5, the throttle shaft 8 includes a cylindrical flange 8 and a threaded extension 8*. The cam 7 is slidable axially on the threaded extension 8 and may be locked in a fixed position by the lock nuts 3 and 8 The pin 8 extends through a hole in the cam 7 so that the cam always is set in the some angular position in relation to the throttle. Each plane of the cam 7 perpendicular to the axis of the threaded portion S represents one governed speed; and the radial contour in this plane varies as explained in connection with Fig. 1. The cam follower 9 of the screw 9 which is secured to the piston 9, contacts the cam in different planes depending on the axial position of the cam 7. Each plane provides a cam for one governed speed that varies as described above. As the cam 7 is moved upward from the position shown in Fig. 5, a new plane having greater radii contacts the cam follower 9 so that a higher governed speed is attained. At each axial position of the cam 7, the radial variation with throttle opening is worked out to give constant R. P. M. at one speed. Conversely, the governed speed is reduced by moving the cam 7 downward as viewed in Fig. 5. As shown in Figs. 1 and 5, the threaded screw 9 may be moved axially in relation to the piston 9 by means of the nut 9 This adjustment serves to determine the initial set of the as sembly of the valve-piece 25, the diaphragm 12, the spring 11, the piston 9, and the screw 9*- so that the valve-piece will be in the correct initial position in relation to the cam 7 considering manufacturing variations. The three dimensional cam shown in Fig. may be replaced by a two dimensional flat cam calibrated to give isochronous speed control at one speed. With this earn, the screw 9 may be adjusted to give a certain amount of speed range, which range is larger at lower speed than at higher speed. With this latter method of speed adjustment, at least three cams are desirable to cover the entire speed range.

Fig. 6 shows another form of the present invention in which the valve-piece 25 has only two valves instead of four as in Fig. l. in Fig. 6 the governor is shown located between the downdraft carburetor 2 and the intake manifold 3. The governor throttle 4 controls the engine only when the carburetor throttle 5 is opened sufficiently to allow the engine to exceed the governed R. P. M. The two valves, 33 and 35, control the pressure only in chamber 19 formed by the power diaphragm 20 through its conduit extension 34, the other chamber 13 communicat ing with the atmosphere through chamber 22 and conduits 22 32, and air filter 26. The spring 51 tends to urge the diaphragm 2 to the left to open the governor throttle 4, whereas the vacuum in chamber 19 tends to close the throttle valve in opposition to the force of spring 51 depending on the position of the valve-piece 25 in exactly the same manner as described in connection with Fig. 1. Also in Fig. 6, a thin metal disc 12* is used instead of the diaphragm 12, Fig. l. The area of the disc substantially equals the area of the piston 9 as shown. The disc is rigidly secured to the valve-piece 25 so the disc is suspended in space by the leaf springs 35 and 36 which suspend the valve-piece 25 The diametrical clearance between the disc 12 and the cylinder 10 is about .003 to .005"; then with the disc substantially centered, there is no metal-to-metal contact and the disc and pilot-valve valr-ze piece 25 are without friction caused by con acting surfaces making them substantially instantly responsive to the slightest change in vacuum in chamber 13. Because of the slight bleed of air between the disc 1.?- and the cylinder wall 10, the passage 13 and 14 must be fairly large without restrictions to insure that the full manifold vacuum is transferred into chamber 13. With the passages 13 and 14 large enough so that no practicable line loss exists there in, even with the valve-piece in its mid-position to give maximum flow, the full unmodified quantitative value of the manifold vacuum is transmitted to act on the disc 12 ft have found it desirable to use a sufficiently large and unrestricted passage to maintain substantially the full unmodified vacuum acting on the disc. This is preferable since any bleedingdown of the manifold vacuum for acting on the speed-sensing element reduces the sensing forces available to the sensing element; the sensing forces (amount of change in vacuum for a given change in speed) are already low to start with, particularly at high speed and at wide-open-throttle, which are the worst conditions for any vacuum governor because of the vacuum curve-shapes inherently characteristic in all gasoline engines. Accordingly, in the preferred arrangement, the disc in this respect is the equivalent of a closed pressure responsive member, such as a metallic bellows for example, which would not have a bleed of air such as passing by the disc. The air bleed past the disc in this preferred arrangement is incidental to the provision of a frictionless pressure responsive sensing member and is not to control pressure in chamber 13. Then the combination of the disc 12 and the pilot-valve or valve-piece 25 which are supported by the leaf springs 35 and 36, all taken with the biasing spring 11 comprise the entire mechanism in my governor that must respond to changes in the speed-vacuum; hence this mechanism might be referred to as the speed-sensing mechanism.

I consider the leaf spring supported valve, and the leaf spring supported disc, or the combination thereof, to be extremely important in the proper operation of an automatic control device such as my governor to regulate a controlled condition such as engine speed. However, all claims to combinations and sub-combinations including a leaf-spring-supported valve or the leaf-spring-supported disc, or combinations thereof, will be made a part of one or more continuing applications. Similarly claims to the self-cleaning or gas-washing feature of using gasoline vapor to keep the disc and valve free of foreign matter will be included in one or more continuing applications, as will claims to the governor release device 17.

Referring to Fig. 6, assume that the engine is accelerated at wide-open throttle up to the governed speed; during the acceleration the valve 35 is substantially closed and the valve 33 is open to the atmosphere because the low vacuum in chamber 13 allows the disc l2 to keep the valve-piece 25 to the left. The valve piece 2.5 remains in this position until the governed speed is attained during the acceleration. The pressure in chambers 18 and 19 is atmospheric whereas the pressure in the manifold gradually decreases; when the governed speed is attained, the valve-piece is moved to the right so that some of whatever vacuum exists in the intake manifold is transferred into chamber 1) to stop the engine from further acceleration. Thus, the manifold vacuum increases during the acceleration period, but the power diaphragm 20 is entirely unaffected until the valve-piece 25 causes it to move toward the closed position. In the class of governors in which the power diaphragm is directely operable by intake manifold pressure, of course, the throttle would be moved gradually toward the closed position during the acceleration period. Tne fact that the power diaphragm 2% in the form of my governor exemplified by Figs. 1 and 6 is substantially independent of variations 17 of manifold vacuum is another of its outstanding features since there is -no restrictionofair flow during acceleration with my governor until the governed speed is attained because the throttle remains wide open during the entire acceleration period.

It has been explained that in Fig. 1 if the cam were calibrated to compensate exactly for the variation. in throttle-vacuum at the governed speed, then the travel of the valve-piece 25 would be responsive only to engine speed. In the power unit of the form of my invention shown in Fig. 6, under the same conditions wherein the movement of the valve-piece would vary solely in accordance with engine speed, the valve-piece would not remain in one position under governor operation; but would assume a new position with each change in engine speed. This fact is apparent because the variable force of the spring 51 that opposes the diaphragm 20 necessitates a changing vacuum in chamber 19 to move the throttle 4 throughout its travel. This changing vacuum can only be produced by a gradual displacement of the valve-piece 25 which displacement must correspond to a small change of engine speed as the load varies from full-load to noload. Hence this governor would inherently have a speed-droop as shown by the curve A--M, Fig. 4, if the cam 7 were calibrated to compensate entirely for the change in throttle-vacuum at the governed speed. Because of the relatively flat slope of the speed-vacuum curves which is characteristic of some engines as illustrated in Fig. l, the speed-droop might be excessive. Hence closer regulation, or isochronous regulation, may be obtained by calibrating the cam 7 with progressively lesser radii at reduced throttle positions whereby less throttle-vacuum is required on the disc 12 to stabilize the governor, whereas this lower vacuum is produced only at progressively lower engine speeds as the load is reduced. Hence although the power unit in the governor illustrated in Fig. 6 would produce a speed-droop if the valve-piece were actuated directly by speed controlled means, the load compensating mechanism embodying a properly contoured cam 7 may be used to provide alower speed-droop, or isochronous operation.

Another optional feature which maybe incorporated in the governor of the present invention, if desired, is the inclusion of a very small air venturi 52 in the air inlet conduit 32. The venturi throat area is only slightly smaller than the entrance and discharge area so that a very slight vacuum of a few inches of water is produced at its throat, and almost all of the inlet pressure is recovered in chamber 41 which is substantially atmospheric. This slight throat vacuum communicates through conduit 53 with the .very small orifice 54 which is exposed to the intake passage on the upstream side of the governor throttle 4. The purpose of the small venturi 52, the conduit 53, and the orifice 54 is to cause a small amount of gasoline vapor to be drawn into the air entering through air filter 26. Then the slight leakage of air with the gasoline vapor past the disc 12 from chamber 41 to chamber 13, and past the clearance of the piston 9 from chamber 22 to chamber 13 continuously keeps the disc and piston clean and free of dirt or grit. Also, the valves 33 and 35 are continuously cleaned in the same manner. Gasoline vapor will flow into the air stream entering through air filter 26 only when the governor throttle is at low-loads at the governor speed when the carburetor throttle is wide open. Then the pressure at the orifice 54 is high enough that a slight reduction at the throat of the venturi 52 will draw gas vapor into the air bleed system. At all other conditions, the vacuum in the intake passage draws a slight amount of air into the engine air stream through conduit 53 and orifice 54 in the reverse direction. This bleed has no effect on the engine operation. The intermittent addition of gasoline vapor to the air bleed system in conduit 32 is sufficient to keep all moving parts clean continuously.

The governor release 17 shown in Fig. 6 communicates with-conduit 34 asshown. If the release is used. with thev governor, the restriction 55 may be inserted inth'e conduit 34 so that the conduit 16. from the release unit connects with conduit 34 between the restriction 551and chamber. 19. When the. chamber 46 is sealed, the governor operation is normal-because only statiovacuum exists in line 34 and 34 Whenthe releaseis broken in the manner. previously described, the valve-piece25 cannot build up the vacuum in chamber 19 because of the bleed throughthe restriction 5E; and conduit 34* so that the spring 51 causes the throttle 4 to snap open and remain openas long as the lead disc 48 is broken.

Fig. 7 shows another. form-ofrny invention which is adapted to. use a liquidunder positive pressure asithe working-fluid in-the' power unit instead, of air asin Figs. 1 and 6. In Fig. 7, the conduit 56 may be. con.- nected to the oil. pressure line which is incorporated in all gasoline engines so that the pressure in conduit-56 is substantially constant owing to a. relief valve inthe engine, all in a manner well-known to those skilled' in the art. Pressure oil flowsin through conduit'56, through the variable orifice 30, through the extension 34 of chamber 19, Fig; 1, through the variable orifice 28, and out through conduits 27 and 57 where the oil is returned. to the enginev oil drain or sump. Also pressure oil flows from conduit 56 through the variable orifice 35, through the extension 29 of chamber 18, Fig. 1, and out through conduits 32 and 57 which is connected to'the engine drain; The pressure in chambers 41 and 41 is atmospheric so that the operation of the diaphragm 12 and'valve-piece 25 by the brain-unit is exactly as described in connection with Fig; 1. When the engine-speed increases, the valve-piece moves to the right so: that the pressurein conduit 29 and chamber 18, Fig. 1, increases and the pressure in conduit 34 and chamber 19, Fig. 1, decreases, causing the diaphragmll), Fig. l, to move to the right and reduce the throttle. openingto restore the governed speed. A decrease in engine speed causes the valve to move in the reverse direction causing the throttleto open.

Referring again to the power fluid circuit in Fig. 6 in comparison with the form shown inFig. 7, itwould be desirable'to. use-a working power fluid; either liquid or gas, whichhas a substantially constant source pressure as'in Fig. 7.. InFig. 6', engine vacuum is used as a power fluid because it is readily available and lends itself to a simple low-cost installation. However, the use of engine vacuum as a power fluid presents the problem that the vacuum available for work at wide-openthrottle positions is low, while at low-throttle positions the vacuum is very high. In Fig. 6, for example, this problem is solved by using an inlet and outlet valve at 33' and35, respectively, for chamber 19, wherein both valves vary oppositely and simultaneously. With this construction, the diaphragm 20 may be selectively subjected to any pressure from the atmospheric pressure in chamber 41 to the full manifold vacuum in chamber 41 depending on the travel-position of the pilot-valve.

The brain mechanism of the present invention, as exemplified in this disclosure, maybe employed in combination with any other device associated with an internal combustion engine that requires a function of speed or load or any combination of engine speed or load. Hence, the present invention should be considered in its broader aspect of providing novel means for extracting from the pressure in the intake manifold an exact indication of any desired function of engine speed or engine load, or any combination thereof.

I am aware that the invention may be embodied in other specificforms without departing from the spirit or essention attributes thereof, and I therefore desire the present embodiments to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than the foregoing description to indicate the scope of the invention.

Having thus described the invention what I claim and desire to secure by Letters Patent of the United States is:

1 A governor for an internal combustion engine comprlsmg means having an intake passage and throttling means therein, a fluid motor for actuating said throttling means, said motor comprising a casing forming a fluid chamber, a member displaceable in said casing dividing said casing into two chambers and operable by fluid pressure differential, means operable to connect said displaceable member and throttle valve for correlated movement therewith, a fluid flow circuit communicating with at least one of said chambers and through which fluid is adapted to be circulated, one end of said circuit being exposed to pressure which is always higher than the pressure in the other end of said circuit at all loads during all governor operating conditions, two fluid restrictions in the said circuit, the communication of said one chamber with the said circuit being at a point between the said two fluid restrictions, at least one of the said restrictions being variable, the flow of fluid past said variable restriction being always in the same direction under governor operation, said variable restriction being operable by a movable pressure responsive sensing member, a pressure chamber, said movable member comprising one wall of said last-named pressure chamber, means to subject said chamber always to substantially the full unmodified quantitative value of the vacuum in the said intake passage, the movement of said variable restriction and cooperating movable member being responsive to variations in pressure in said chamber, and means connected to said throttle and operable in accordance with the opening of said throttle to control the diflerential of the forces acting on the said movable member, whereby the movement of said movable member is made responsive substantially solely to the changes in pressure resulting from changes in engine speed.

2. In a governor for an internal combustion engine having an intake passage and throttling means therein, the improvement comprising in combination a fluid motor for actuating said throttling means, said motor comprising a casing forming a fluid chamber, a member displaceable in said casing dividing said casing into two chambers, means operable to connect said member and throttling means for correlated movement therewith, a fluid flow circuit during all governor operating conditions having one end connected to said intake passage and its opposite end connected to substantially atmospheric pressure, said circuit communicating with at least one of said chambers and through which fluid is adapted to be circulated, two fluid restrictions in said circuit, the chamber associated with the fluid flow circuit being in communication with the said fluid flow circuit at a point between said last-named two fluid restrictions, at least one of the said restrictions being variable, said variable restriction being operable by a movable pressure responsive sensing member, biasing means urging said movable pressure responsive sensing member in one direction, a pressure chamber, said movable member comprising one wall of said last-named pressure chamber, means to subject said chamber to pressure that varies in accordance with the pressure variation in the said intake passage, the movement of said variable restriction and cooperating movable member being responsive to variations in pressure in said chamber, the pressure difierential across the said movable member opposing the force of the said resilient means, a cam connected to said throttling means and operable in accordance with changes in position thereof and acting on said biasing means to increase its force as said throttling means closes whereby to compensate for the changes in pressure acting on said movable member resulting from changes in position of said throttling means, whereby the movement of said movable member is made responsive substantially solely to the changes in pressure resulting from changes in engine speed.

3 In a governor for an internal combustion engine having an intake passage and throttling means therein the improvement comprising in combination, a fluid motor for actuating said throttling means, said motor comprising a casing including a chamber, a member displaceable in said casing comprising one wall of said chamber, means operable to connect said displaceable member and throttling means for correlated movement therewith, resilient means urging said displaceable member in one direction, a fluid flow circuit during all governor operating conditions having one end conected to said intake passage on the downstream side of said throttling means and its opposite end connected to substantially atmospheric pressure, said circuit communicating with said chamber and through which fluid is adapted to be circulated, two fluid restrictions in the said circuit, the said chamber being in communication with the said fluid flow circuit at a point between the last-named two fluid restrictions, the pressure in the said chamber in relation to the pressure on the side of said displaceable member not included in said chamber causing the said displaceable member to oppose the force of said resilient means, at least one of the said restrictions being variable, said variable restriction being operable by a movable pressure responsive sensing member, second resilient means urging said movable member in one direction, a pressure chamber, said movable pressure responsive sensing member comprising one wall of said last-named pressure chamber, means to subject said chamber to pressure that varies in accordance with the pressure variation in the said intake passage, the movement of said variable restriction and cooperating movable member being responsive to variations in pressure in said chamber, the pressure diflerential across the said movable member opposing the force of said last-named resilient means, a cam connected to said throttling means and operable in accordance with changes in position thereof and acting on said second resilient means to increase its force as said throttling means closes whereby to compensate for the changes in pressure acting on said movable member resulting from changes in position of said throttling means, whereby the movement of said movable member is made responsive substantially solely to the changes in pressure resulting from changes in engine speed.

4. A governor for an internal combustion engine comprising means having an intake passage and throttling means therein, a device operable by fluid differential pressure for actuating said throttling means, means including pressure responsive means to control the said pressure differential in said device, a pressure chamber, said pressure responsive means comprising one wall of said chamber, said chamber having a second movable wall enclos ing pressure in said chamber, and means mechanically connecting said last-named movable wall with said throttling means to effect movement of said second wall in accordance with changes in position of said throttling means.

5. A governor for an internal combustion engine comprising means having an intake passage and throttling means therein, a device operable by fluid pressure differential for actuating said throttling means, means including displaceable means to control the said pressure differential in said device whereby to effect movement of said throttling means, a pressure chamber, said displaceable means comprising one wall of said chamber, means mechanically connecting another wall of said chamber with said throttling means to effect movement of said second wall in accordance with changes in position of said throttling means, and resilient means urging said two walls in different directions.

6. A governor for an internal combustion engine comprising means having an intake passage and a throttle valve therein, a motor for actuating said throttle valve, said motor comprising a casing, a member displaceable in said casing operable by differential pressure to actuate said throttle valve and dividing said easing into two fluid chambers, a fluid circuit communicating with at least oneof said chambers, valve meansin said circuit to control pressure in said circuit acting on said displaceable member, said valvemeans being so arranged in relation to said circuit and said displaceable member that movements of said displaceable member are produced in response to movements of said valve means during all governor operating conditions, a movable pressure-responsive sensing member for actuating said valve means, the movement of said valve means controlling the said diflerential pressure, a pressure chamber,- said movable member comprising one Wall of said'chamber, resilient means, the force of said resilient means opposing the pressure differential across the said movable member, means mechanicallyconnecting one end of said resilient means with said throttle valve for varying the force of said resilient means in accordance With changes in position of said throttle valve, and said valve means being so arranged in cooperation with said circuit that during all governor operating conditions any change of engine speed produces movement of said valve meanswhich effects a corresponding movement ofsaid displaceable member always in a direction tending to restore the governed engine speed.

7. In a governor for controlling the speed of an internal combustion engine having an intake passage for the flow of air therethrough in which the pressure varies as a result of a change in position of a throttle in said passage and also as a result of a change in engine speed at fixed positions of said throttle, the improvement comprising the combination of a governor throttle in said intake passage, a pressure responsive member operatively connected to said throttle for actuation thereof, a fluid flow circuit communicating with said pressure responsive member, valve means in said fluid circuit to control pressure therein acting on saidpressure responsive member to effect movement thereof, said valve means being so arranged in relation to said circuit and said pressure responsive member that movements of said pressure responsive member are produced in response to movements of said valve means during all governor operating conditions, a second pressure responsive member exposed to substantially the full unmodified quantitative value of the vacuum in said intake passage during all governor operating conditions and controlled by pressures in said intake passage, said second pressure responsive member acting on said valve means to effect movement thereof in response to changes in intake passage pressure at fixed positions of said throttle, and movable means connected to said governor throttle and operating to position said valve means in-accordance with changes in position of said throttle to compensate for the changes in intake passage pressure acting on said second pressure responsive member resulting rom changes in the position of said throttle, whereby said second pressure responsive member is responsive substantially solely to changes in intake passage'pressure resulting from changes in engine speed, andsaid valve means being so arranged in cooperation with said circuit that during all governor operating con ditions any change of engine speed produces movement of said valve means which effects a corresponding movement of said pressure responsive member always in a direction tending to restore the governed engine speed.

8. The combination of elements defined in claim 7, and,said fluid circuit having its outlet end connected to the intake passage on thedownstream side of said throttle and its inlet end connected to a region of pressure always higher than the pressure in said intake passage on the downstream side of said throttle at all loads during all governor operatingconditions, and said second pressure responsive member beingexposed at the downstream side of said throttle to said substantially full quantitative value of the vacuum in=.s'aid intake passage.

9; In a governor for automatically controlling the speed of an internal combustion engine having an intake passage-:for the flow of air therethrough, said governor including a fluid force-amplifying, mechanism using intake-passage vacuum asa source of power in .saidrnechanism, the combination of a throttle'operatively' mounted in said intake passage to control engine speed, a pressure responsive member connected to said throttle for actuation thereof, a fluid circuit connected at its inlet port during all operating conditions to substantially constant atmospheric air pressure and at its outlet port to the vacuum in said passage on the downtream side of said throttle, two restrictions in said circuit, said pressure responsive member communicating with said circuit at a point between said two restrictions therein to provide pressure for, actuating said member, said member being subjectable on only one side thereof to pressure in'said circuit between said restrictions and on the other side thereof to substantially constant fluid pressure, a spring opposing thefluid force acting on said pressure responsive member as-a result of said actuating pressure in said circuit, movable means including valve means responsive to changes in the full unmodified quantitative value of the maximum available forces produced as a function of engine speed to vary the restrictive effect of both of said restrictions in response to changes in engine speed, for modulating said actuating pressure throughout the entire range of pressures from the value of pressure at said inlet port to the value of pressure at said outlet port in order to make selectively available any actuating pressure between the said constant air pressure and the pressure corresponding to the total intake passage vacuum for effecting desired movement of said pressure responsive member in all operating positions.

10. The construction defined in clainr7 in which the means associated with said governor throttle includes a cam connected to said throttle and operating to position said valve means.

11. in a governor for an internal combustion engine having an intake passage for the flow of air therethrough, the improvement comprising the combination of a governor throttle operatively mounted within said passage to control the engine, a pressure responsive member connected to said throttle for actuating the same, a circuit during all governor operating conditions havingone end connected to said'intake passage on the downstream side of the throttle and its opposite end connected to a region of substantially constant pressure higher than the pressure at the end of said circuit connected to said intake passage, said circuit adapted in operation of the engine to have fluid flowing therethrough, said pressure responsive member being subjected to pressure in, said fluid circuit, valve means to control said last-named pressure in said fluid circuit acting on said pressure responsive member for establishing the position thereof, second pressure responsive means controlled by pressure in said passage on the engine side of said throttle to actuate said valve means in response to the intake passage pressures on the engine side of said throttle at fixed positions of said throttle, spring means to exert predetermined forces on said second pressure responsive means, and means actuated by said throttle to position one end of said spring means in accordance with positions of said throttle and acting to increase the force of said spring means as said throttle closes to compensate for changes of intake passage pressures acting on said second pressure responsive member and resulting from movements of the throttle effected by changes in engine load, whereby said second pressureresponsive means is responsive substantially solely to changes in intake passage pressure resulting from changes in engine speed.

12. The construction defined in the claim 7, the movable means connected to said governor throttle including a cam having a three dimensional controlling'surface disposed to position said valve means.

13. In a governor for controlling the speed of an internal combustion engine having an intake passage for the flow of air therethrough, the improvement comprising in combination a governor throttle operatively mounted within said passage to control the engine, a pressure-responsive member connected to said throttle for actuating the same, a circuit adapted in operation of the engine to have fluid flowing therethrough, one end of said circuit being exposed to pressure which is always higher than the pressure in the other end of said circuit at all loads during all governor operation, said pressureresponsive member being subjected to pressure in said fluid circuit, valve means to control said pressure in said fluid circuit acting on said pressure responsive member for establishing the position thereof, said valve means including second pressure responsive means movable in response to substantially the unmodified quantitative value of the full intake passage pressures on the downstream side of said throttle at fixed positions of said throttle during all governor operations, the flow of fluid past said valve means being always in the same direction, and movable means associated with said governor throttle to control the effective opening of said valve means, said movable means varying in accordance with positions of said throttle to compensate for changes of intake passage pressures acting on said pressure responsive means and resulting from movements of the throttle effected by changes in engine load, whereby said second pressure responsive means is responsive substantially solely to changes in intake passage pressures resulting from changes in engine speed.

14. In a governor for an internal combustion engine having an intake passage for the flow of air therethrough in which the pressure varies as a result of a change in engine speed and also as a result of a change in position of a throttle in said passage, the improvement comprising the combination of a governor throttle in said intake passage, a device including pressure responsive means exposed always to substantially the unmodified full quantitative value of the vacuum in said intake passage on the downstream side of said throttle at fixed positions thereof to cause movement of said throttle, means biasing said pressure responsive means in one direction, and a cam operated by movement of said throttle to position said biasing means to increase its force as said throttle closes whereby to maintain said pressure responsive means in such a position as to compensate for the changes in pressure on said pressure responsive means resulting from changes in the position of said throttle, whereby the movement of said pressure responsive means is made responsive substantially solely to the change in pressure resulting from changes in engine speed, and said pressure responsive means being so arranged in said device in cooperation with said throttle that during all governor operating conditions any change of engine speed produces a movement of said pressure responsive means which effects a corresponding movement of said throttle always in a direction tending to restore the governed engine speed.

15. In a control device for an internal combustion engine having an intake passage for the flow of air therethrough and a throttle operatively mounted therein for controlling the engine, a circuit adapted in operation of the engine to have fluid flowing therethrough, a variable orifice including valve means to control the flow of fluid in said circuit, pressure responsive means for actuating said valve means to vary the aperture of said orifice, a pressure chamber communicating with said intake passage, said pressure responsive means comprising a movable wall of said chamber, said chamber having a second movable wall disposed to enclose the pressure in said chamber, spring means connecting said two movable Walls urging said walls in different directions, and movable means connected to and operated by said throttle to move said last-named movable wall whereby to aid in determining the aperture of said orifice.

16. In a control device for an internal combustion engine having an intake passage for the flow of air therethrough and a throttle operatively mounted therein for controlling the engine, a circuit adapted in operation of the engine to have fluid flowing therethrough, an orifice including valve means to control the flow of fluid through said circuit, pressure responsive means connected to said valve means for actuation thereof to vary the aperture of said orifice, a pressure chamber communicating with said intake passage on the engine-side of said throttle, said pressure responsive means comprising a movable wall of said chamber, said chamber having a second movable wall disposed to enclose said chamber, spring means between said two movable walls urging said walls in opposite directions, and cam means effectively connected to and operated by said throttle to move said last-named movable wall to control at least in part the aperture of said orifice.

17. in a self-regulating control mechanism for automatically controlling a variable condition, the combination of control means to regulate said controlled condition, a pressure responsive member connected to said control means for actuation thereof, a fluid circuit having two restrictions therein for the flow of fluid therethrough, one end of said circuit being exposed to pressure which is always higher than the pressure in the other end of said circuit, said member communicating directly with said fluid circuit at a point between said two restrictions, biasing means having a variable force acting on said pressure responsive member to oppose the forces produced thereon by fluid pressures in said circuit acting on said member, the force of said biasing means varying as a function of the movement of said member, valve means in said circuit for modulating the aperture of at least one of said restrictions for varying only the pressures acting on one side of said pressure responsive member to effect movement thereof as a function of the movement of said valve means, sensing means responsive to changes in said controlled condition and acting on said valve means to produce movements thereof for efiecting movements of said pressure responsive member and amplified forces acting on said control means, second biasing means having a varying force acting on said valve means to oppose the forces produced by said sensing means, the force of said second biasing means varying as a function of the movement of said valve means, whereby the movement of said valve means varies as a function of said controlled condition to effect corresponding movement of said control means and also as a function of said controlled condition for maintaining within a predetermined variation a desired value of said controlled condition, and means connected to said control means and acting on said second biasing means for varying the force thereof in accordance with the movement of said control means to control said variation of the desired value of said controlled conditions.

18. In a speed governor for an internal combustion engine having an intake passage, the improvement com prising, in combination, means including rotatable throttling means in said intake passage for controlling engine speed and movable in response to changes in pressures therein, and an axially movable cam having a three dimensional controlling surface connected to rotate with said throttling means and acting on said first named means, whereby the engine may be closely controlled throughout a selectably wide range of engine speeds.

19. in a governor for controlling the speed of an internal combustion engine having an intake passage for the flow of air therethrough in which the pressure varies as a result of a change in position of a throttle in said passage and also as a result of a change in engine speed at fixed positions of said throttle, the improvement comprising, in combination, means including throttling means in said intake passage for controlling engine speed'and movable in response to changes in pressure in said intake passage at fixed positions of said throttling means, and a cam having a three dimensional controlling surface connected to move in accordance with changes in position of said throttling means and acting on said first named means, to compensate for changesin pressure acting on said first named means resulting from changes in the positionof said throttling means effected by changes in engine load, whereby the movement of said throttling means is responsivev substantially solely to changes of intake passage pressure resulting from changes in engine speed to maintain within a predetermined variation a-desired engine speed, and adjusting means to shift said cam to alter its effective contour.

20. In a self regulating control mechanism for automatically controlling a variable condition the combination of, control means to regulate said controlled condition, a pressure responsive member connected to said control means for actuation thereof, a fluid circuit having flow of fluid therethrough and communicating with said member, movable means including valve means in said circuit controlled by said controlled condition to regulate the flow of fluid through said circuit in response to changes in said controlled condition-for controlling the pressures insaid circuit acting on said pressure responsive member, whereby to eflect movement of said member with amplified forces for movements of said control means for maintaining within a predetermined'variation a desired value'of said controlled condition, means including a cam connected to said control means for simultaneous movement therewith and follower means cooperating with the cam to control forces'acting on said valve means for regulating said variation of the desired value of said controlled=condition, said'cam including a three-dimensional controlling surface, said cam and its follower means being relatively shiftable from one set position to another in'a direction diii'erent from the direction of its move ments with said control means for utilizing the various portions of said controlling surface, said surface being disposed in any one of said shiftable positions to control the forces acting on said valve means as a definite predetermined-functional relationship to the corresponding movements of said control means, and'means to reposition, said cam to, another of said shiftable. positions to change to another. definite predetermined functional relationship ofsaid forces acting on said valve means to movements of said control means.

21. In a-self regulatingcontrol mechanism for automatically controlling a variable condition the combination of, control-meansto regulate said controlled condition, a pressure responsive member connected to said control means for actuation thereof, a fluid circuit having; two restrictions therein for the flow of fluidtherethrough, said pressure responsive member communicating with said fluid circuit at a point between said two restrictions, valve means in said circuit for varyingthe aperture of at least one of said restrictions for controlling pressures in said circuit acting on said member to. effect movement thereof, said valve means being so arranged in relation to said circuit and said pressure responsive member.that movements of said pressure responsive member are. produced in response to movements of said valve meansduring all governor operating conditions and at all positions of said control means, movable sensing means responsive to changes in said controlled condition and acting on said valve means to effect movement thereof fOl'i producing movements of'said pressure responsive member and thereby amplified movements acting on said control means for maintaining within a predetermined variation a desired value of said controlled condition, biasing means acting on said valve means to oppose the forces produced by said sensing means, and means connected to said control means and acting on said biasing means for varying the force thereof in accordance with the movement of said control means to control said variation of the desired value of said controlled condition.

22. The combination of means defined in claim 7, and adjusting means disposed to vary selectively the position of said valve means in relation to said movable 26 means, said adjustment of said-relationship comprising the sole means forsetting the speed of the. governor.

23. The combinationof means defined inv claim 7 in which said circuit'includestwo restrictions-therein, said communication of said first pressure responsive member being between said two restrictions, and said valve means being disposedto varythe restrictive effect of both of said two restrictions.

24. The combination'of elements defined in claim 7, and said fluid circuit having its outlet port connected to the vacuum in said intake passage on the downstream side of said throttle and: its inlet'port connected to a region of substantially atmospheric air pressure during all governor operating conditions, two restrictions in said circuit, said first pressure responsive member communicating with said circuit at a point between said two restrictions, whereby said valve means controls pressure actuating said first pressure responsive member to' effect a closing movement of said'throttle, saidfirst pressure responsive member being subjectable on only one side thereof to pressure in said circuit between said restrictions and on the other side thereoftosubstantially constant fluid pressure, aspring opposing the fluid force acting on said first pressure responsive member as a result of said actuating pressure in said circuit, said spring being arranged to effect an opening movement of said throttle, said valve means varying simultaneously and oppositely the restrictive efiect of both of said restrictions in response to changes in engine speed to modulate said actuating pressure throughout the entire range of pressures from the value'of pressure at said inlet port to the value of pressure at said outlet port to make selectively availableany actuating pressure between the value of the said atmospheric pressure and the value of the pressure. corresponding to the total intake passage vacuum for elfecting-desired movement of said first pressure'responsive member in all operating conditions.

25. The combination of elements defined in claim 9. in which said spring is so arranged in relation to said pressure responsive member and said throttle to urge same in its opening direction, and said throttle opening is reduced as a result of vacuum in said circuit between said restrictions selectively established by said valve means to overpower the force of said spring, said spring force then increasing as the throttle opening is reduced, the said restriction further from said intake passage comprising an air inlet orifice andsaid restriction closer to said intake passage comprising an air outlet orifice, said variation of said two restrictions being simultaneous and opposite, said two restrictions and said valve means and said throttle and said pressure responsive member being so arranged in relation to each otherthat said valve-means can fully close said inlet orifice while opening said outlet'orifice to direct the full intakev passage vacuum to saidpressure responsive member when required at wide-open-throttle positions and can fully close said outlet orifice. while opening said inlet orifice at the other extreme condition to transfer the full value of the said constant atmospheric air pressure to said pressure responsive member when required to permit said spring to exertits maximum throttle-opening force when saidthrottle is at'a low opening and the intake passage vacuum is high.

26. The combination of elements defined in claim 7, and said second pressure responsive member being exposed at the downstream side of said throttle to said substantially full quantitative value of the vacuum in said intake passage, a spring biasing said second pressure responsive member, and said movable means being disposed effectively to act on one end of said spring to produce load-compensating movements thereof, said second pressure responsive member being disposed to act effectively on the other end of said spring to produce speed-sensing movements thereof, said movable means being disposed to determine the functional relationship of the movement of said throttle to the said compensating movements of .said spring end to accommodate a change in the length of said spring effected by said intake manifold pressure acting on said second pressure responsive member to increase the force of said spring as said throttle closes, for establishing said valve means in the desired positions at all engine loads during all governor operation to compensate for said variation of intake manifold pressure acting on said second pressure responsive member resulting from changes in the position of said throttle, whereby to maintain the desired engine speed during governor operation.

27. The combination of elements defined in claim 26, in which said movable means is disposed to act directly on said load compensating end of said spring to effect movement thereof an amount substantially equal to the amount of the corresponding movement of said movable means at the effective connection thereof with said load compensating spring end.

28. The combination of elements defined in claim 7, and said fluid circuit having its outlet end connected to the intake passage on the downstream side of said throttle and its inlet end connected to a region of pres sure which is substantially constant during all governor operating conditions, and said second pressure responsive member being exposed at the downstream side of said throttle to said substantially full quantitative value of the vacuum in said intake passage, said circuit including two restrictions, said communication of said first pressure responsive member with said circuit being at a point between said two restrictions, said valve means being disposed to vary the restrictive effect of at least one of said two restrictions to control said pressure acting on said first pressure responsive member for establishing the position thereof, a spring biasing said second pressure responsive member, and said movable means including a cam connected to said governor throttle for simultaneous movement therewith, said cam being disposed effectively to act on one end of said spring to produce load-compensating movements thereof, said second pressure responsive member being disposed effectively to act on the other end of said spring to produce speed-sensing movements thereof, the contour of said cam being disposed to accommodate a change in the length of said spring effected by said intake manifold pressure acting on said second pressure responsive member to increase the force of said spring as said throttle closes, for establishing said valve means in the desired operating positions at all engine loads during governor operation to compensate for said variation of intake manifold pressure acting on said second pressure responsive member resulting from changes in the position of said throttle, whereby to maintain the desired engine speed during governor operation.

29. The combination of elements defined in claim 20, in which said cam-repositioning means is manually operated.

30. The combination of means defined in claim 7, and said movable means including a cam movable in accordance with movements of said throttle and including a three-dimensional controlling surface, said cam being shiftable from one set position to another in a direction transverse to said direction of said firstnamed cam movement for utilizing the various portions of said controlling surface, a spring biasing said second pressure responsive member, and said surface being disposed in any one of said shiftable positions effectively to act on one end of said spring to produce load-compensating movements thereof, said second pressure responsive member being disposed to act effectively on the other end of said spring to produce speed-sensing movements thereof, the contour of said cam being formed to determine the functional relationship of the movement of said throttle to the said compensating movements of said spring end to accommodate a change in the length of said spring effected by said intake manifold pressure acting on said second pressure responsive member to increase the force of said spring as said throttle closes, for establishing said valve means in the desired positions at all engine loads during all governor operation to compensate for said variation of intake manifold pressure acting on said second pressure responsive member resulting from changes in the position of said throttle whereby to maintain a desired engine speed during governor operation, and means to reposition said cam to another of said shiftable positions to change to another predetermined functional relationship of said movement of said throttle to said compensating movements of said spring end to produce a governed engine speed different from said firstnamed engine speed.

31. The combination of elements defined in claim 17 in which said second biasing means comprises spring means acting on said valve means, and said means connected to said control means includes cam means acting on said spring means to vary the force thereof as a function of the movement of said control means.

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